1. Field of the Invention
The present invention relates to a boron carbide sintered body having high hardness and being excellent in terms of grindability and a method of manufacturing the boron carbide sintered body. The present invention also relates to a protective body that reduces the penetration of a flying object such as a bullet and a shell in order to protect a human body, a vehicle, a ship, or an aircraft. The present invention further relates to a protective body that can be suitably used for a protective barrier or the like for a building.
2. Description of the Related Art
In general, boron carbide is lightweight and has a high hardness near that of diamond and cubic boron nitride, and also high mechanical strength. Thus, boron carbide has been used for abrasion-resistant members. For a boron carbide sintered body, in order to effectively utilize such advantageous high hardness of boron carbide, sinterability of the boron carbide sintered body needs to be sufficiently increased. Boron carbide, however, is a sintering-resistant material. Thus, it has been difficult to sufficiently increase the sinterability of a boron carbide sintered body by using a conventional sintering technique. A technique for sufficiently increasing the sinterability of a boron carbide sintered body has been developed.
Japanese Examined Patent Application Publication No. 2-053387 discloses a technique for producing a boron carbide sintered body by pressureless-sintering a fine-grained mixture of α-silicon carbide, boron carbide, carbon, and an organic material that can be coked to form carbon to form a sintered body and then repressurizing the resulting sintered body in a high-pressure autoclave using an inert gas as a pressure-transfer medium.
However, a boron carbide sintered body having higher grindability than that of the boron carbide sintered body disclosed in Japanese Examined Patent Application Publication No. 2-053387 is required while high hardness is maintained.